Mathematics 5 curriculum guide 2015 I table of contents acknowledgements

Resources/Notes
ADDING AND SUBTRACTING DECIMALS
General Outcome: Develop Number Sense
Authorized Resource
Performance
• 
Model 2.12 and 1.140 with base ten blocks. Ask students to use the 
materials to explain how to find the difference between the two numbers.
(5N11.4)
• 
Ask students to work in pairs. Each student should measure 10 
of their own foot lengths in metres to the nearest millimetre (i.e., 
thousandth of a metre). They should find the sum of the measures 
of the two partners and the difference between the two lengths. 
They could share their results with other groups and repeat the 
comparisons with another pair of students.
(5N11.4)
Paper and Pencil
• 
Jacob has grown two sunflowers. One of the sunflowers is
80.254 cm tall and the other is 86.49 cm tall. What is the difference 
in the heights of the two sunflowers?
(5N11.4)
Math Focus 5
Lesson 6: Exploring Problems that 
Involve Decimals
TR: pp. 40-42
SB: p. 100
Curious Math:
Subtracting Decimals Using a 
Whole Number
TR: pp. 43-44
SB: p. 101
Lesson 7: Subtracting Decimals by 
Regrouping
TR: pp. 45-49
SB: pp. 102-105

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MATHEMATICS 5 CURRICULUM GUIDE 2015
Specific Outcomes
ADDING AND SUBTRACTING DECIMALS
Suggestions for Teaching and Learning
Students will be expected to:
Number
Students could also use the comparison model for subtraction of decimals 
using base ten materials, where the focus is on finding the difference 
between the two numbers. In this case, students could model both 
numbers and compare. The difference between them is the solution.
Ask students to model using their base ten materials and record their 
solution pictorially and symbolically. Students should continue to use 
estimation to determine the correct placement of the decimal.
The answer would be the blocks remaining in the top model or 1.404.
Each summer, Sarah and her family pick bakeapples and sell them. This 
year, Sarah picked 2.75 L and her brother picked 1.346 L. How much 
more did Sarah pick than her brother?
When modelling with pictures or diagrams, students could circle what is 
being traded and cross out what has been subtracted. They may need to be 
reminded to move over what has been traded by redrawing in the new place 
value section.